JPH0776255B2 - Glycidyl ether of novolac type phenolic resin and encapsulant containing it as a main component - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novolac-type phenol resin, a glycidyl ether thereof, and a sealant containing these as a main component, which are raw materials for a heat-resistant epoxy resin.

<Prior Art> As the heat-resistant epoxy resin which is widely marketed at present, there are glycidyl ether of phenol novolac and glycidyl ether of 0-cresol novolac.

These epoxy resins are used in fields where heat resistance is particularly required, for example, sealing materials for semiconductor integrated circuits, laminated boards for printed wiring boards and the like.

<Problems to be Solved by the Invention> However, the requirements for heat-resistant epoxy resins are becoming stricter year by year, and higher heat resistance is required.

At the same time, it is usually required to have flexibility which is a physical property contrary to heat resistance.

For example, for sealing semiconductor integrated circuits, a material that relaxes internal stress and is excellent in crack resistance is required.

This internal stress is expressed by the product of the coefficient of linear expansion and elastic modulus,
A material having a low coefficient of linear expansion and a low elastic modulus is desired.

Further, in the case of a laminated board such as a printed wiring board, improvement in drill workability is required, and a material having a low elastic modulus is desired.

The present invention provides a well-balanced epoxy resin material having a high glass transition temperature and a low elastic modulus, and an encapsulant for electronic parts for the use thereof.

<Means for Solving Problems> The present invention is as follows.

(1) Formula (III) (Wherein R ¹ , R ² and R ³ are each selected from the group consisting of hydrogen atom, hydrocarbon group and halogen atom, and n is a number from 2 to 50) Glycidyl ether.

(2) Formula (IV) (Wherein R ¹ , R ² and R ³ are each selected from the group consisting of a hydrogen atom, a hydrocarbon group and a halogen atom, and n is a number of 2 to 50). Glycidyl ether of the described novolak type phenolic resin.

(3) Formula (III) (Wherein R ¹ , R ² and R ³ are each selected from the group consisting of hydrogen atom, hydrocarbon group and halogen atom, and n is a number from 2 to 50) An encapsulating material containing glycidyl ether as a main component.

(4) Formula (IV) (In the formula, R ¹ , R ² and R ³ each represent a hydrogen atom, a hydrocarbon group, and a halogen atom,
(n represents a number of 2 to 50), The sealing material according to the item (3).

The compound represented by the formula (III) has the formula (I) (Wherein R ¹ , R ² and R ³ are each selected from the group consisting of hydrogen atom, hydrocarbon group and halogen atom, and n is a number from 2 to 50) Is obtained by glycidyl etherification.

Specific examples of the substituents R ¹ , R ² and R ³ include a hydrogen atom, a methyl group, a butyl group, a phenyl group, a chlorine atom and a bromine atom, and a hydrogen atom and a bromine atom are preferable.

The number of repeating units n is 2 or more and 50 or less.

When n exceeds 50, a large amount of a high molecular weight product is produced, and the glycidyl ether has a high viscosity even under high temperature conditions, which makes handling difficult.

Further, when n is less than 2, the glycidyl ether becomes a semi-solid or viscous liquid at room temperature and becomes difficult to handle.

The novolac type phenolic resin of formula (I) has the formula (R ¹ , R ² , and R ³ are the same as those in formula (I)), and are obtained by polymerizing p-isopropenylphenols represented by the formula (I) in the presence of an alkali catalyst.

As a method for synthesizing this p-isopropenylphenol, there is a method by thermal decomposition of bisphenol represented by bisphenol A as shown in Japanese Patent Publication No. 38-1368 or a method by dehydrogenation of p-isopropylphenol. Are known.

In both of these methods, the product contains phenol or saturated alkyl group-substituted phenols as impurities.

The p-isopropenylphenols thus synthesized are polymerized in the presence of an alkali catalyst to obtain a compound of formula (II) A novolac-type phenol resin represented by the formula (wherein R ¹ , R ² , and R ³ represent a hydrogen atom, a hydrocarbon group, or a halogen atom, and n represents a number of 2 to 50) is mainly obtained.

Incidentally, the above-mentioned impurities do not hinder the polymerization reaction.

The alkali catalyst used in this polymerization reaction is preferably an alkali metal or alkaline earth metal hydroxide, more preferably sodium hydroxide, potassium hydroxide or the like.

The amount of the alkali catalyst used is about 0.001 to 0.1 mol with respect to 1 mol of p-isopropenylphenols.

The polymerization temperature is 140 ° C to 250 ° C.

If the temperature is 140 ° C or lower, it is difficult to obtain a sufficient degree of polymerization, and if the temperature is 250 ° C or higher, the polymer is easily decomposed, which is not preferable.

This polymerization reaction can be carried out under atmospheric pressure, but can also be carried out under reduced pressure by removing the above-mentioned impurities existing in the system out of the system.

If the novolac type phenolic resin represented by the general formula (II) is glycidyl etherified, the formula (IV) is obtained. (Wherein R ¹ , R ² and R ³ are each selected from the group consisting of hydrogen atom, hydrocarbon group and halogen atom, and n is a number from 2 to 50) Of glycidyl ether.

Glycidyl etherification of novolac type phenolic resins is usually used for producing the glycidyl ether from a monohydric or polyhydric phenol by reaction with epichlorohydrin as shown in JP-A-58-189223. The applicable method can be applied.

A composition containing the glycidyl ether as a main component thus obtained and a curing agent mixed therein can be suitably used as a raw material for electric and electronic materials.

Currently, semiconductor encapsulation materials that are becoming higher in density and larger in size are required to have good heat resistance, that is, high glass transition temperature and low stress, that is, low elastic modulus, which are incompatible with each other. The encapsulating material containing glycidyl ether of the novolak type phenolic resin represented by the formula (III) or the formula (IV) as a main component can meet this demand.

In this encapsulating material, in addition to the glycidyl ether, a curing agent such as phenol novolac, m-cresol novolac, resorcin novolac, and other novolac-type phenols, vinylphenols such as vinylphenol polymers and isopropenylphenol polymers, and toyethylene. Aliphatic amines such as triamine, triethylenetetramine, tetraethylenepentamine, dimethylaminopropylamine, diethylaminopropylamine, aminoethylethanolamine, alicyclic amines such as menthanediamine, n-aminoethylpiperazine, metaphenylenediamine, Diaminodiphenylmethane, diaminodiphenylsulfone, metaxylenediamine, metaaminobenzylaminebenzidine, 4-chloro-o-phenylenediamine, bis (3 , 4-diaminophenyl) sulfone, aromatic amines such as 2,6-diaminopyridine, polyamide resin, pyromellitic anhydride, succinic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride,
There are acid anhydrides such as maleic anhydride, methyl nadic acid anhydride, glutaric anhydride, and tetrabromophthalic anhydride. Among them, novolac type phenols such as phenol novolac and m-cresol novolac, vinylphenol polymers, isopropenylphenol. Vinylphenols such as polymers are preferred.

In addition, inorganic fillers such as silica, alumina, talc, clay and glass fibers, hardening accelerators such as imidazoles and tertiary amines, internal release agents such as stearic acid, calcium stearate, carnauba wax and montan wax are usually used. Compound.

The encapsulant is generally used when encapsulating a semiconductor integrated circuit by transfer molding.

The composition ratio of the encapsulant varies depending on each type, but in principle, the curing agent is compounded in such an amount that the curing agent has the same number of moles of the functional group of the curing agent as the moles of the epoxy group of the glycidyl ether, and the filler is An amount that makes the filler almost close to the closest packed volume with respect to the total blended amount, a small amount of the curing accelerator such as a catalytic amount, and an internal release agent of about 0.2 to 2.0% by weight based on the total blended amount. Is the amount of.

<Example> Hereinafter, an example of the present invention will be described.

In the examples, the softening point is measured by JIS-K2531 (petroleum asphalt softening point test method (ring and ball method)).

The epoxy equivalent is defined as gram equivalent per mol of glycidyl ether group.

The glass transition temperature and elastic modulus were measured with Rheolograph Solid (manufactured by Toyo Seiki Co., Ltd.).

¹³ C-NMR spectroscopy (Hitachi FT-NMR, R-90H) using deuterium-substituted chloroform as a solvent for the structural analysis of polymers
Went by.

Example 1 (1) Production of novolac type phenol resin A mixture obtained by thermal decomposition of bisphenol A (p-isopropenylphenol 48 wt%, phenol 42 wt%, according to the description of Example 1 in Japanese Examined Patent Publication No. 38-1368). p-isopropenylphenol oligomer 10wt%) 300g,
Add 2.69 g of 48% NaOH aqueous solution and heat to 180 ° C under reduced pressure (50 Torr) while distilling phenol.

Further, the temperature is kept at 180 ° C. for 4 hours to complete the polymerization.

After the polymerization was completed, the reaction product was poured into a large amount of dilute aqueous HCl solution,
A polymer was precipitated to obtain a yellowish brown resin.

The softening point of this resin was 105 ° C.

The ¹³ C-NMR chart of this resin is shown in FIG.

Assignment of peaks in the ¹³ C-NMR chart in FIG. 1 is as follows.

29-33ppm 41-43ppm Aromatic ring carbon 114-156ppm (2) Synthesis of glycidyl ether of novolac-type phenol resin Thermometer, separation tube, dropping funnel, stirrer attached 1
In a flask, 1.0 mol of the novolac-type phenol resin (as a phenolic hydrogen group) obtained in (1) of Example 1 is dissolved in 7.0 mol of epichlorohydrin.

While maintaining the temperature at 80 ° C. and the pressure at 250 mmHg, 48% NaOH aqueous solution was continuously added within 6 hours.

During this time, epichlorohydrin and water were azeotropically liquefied to be liquefied and separated into an organic layer and an aqueous layer by a separation tube, the aqueous layer was removed outside the system, and the organic layer was circulated inside the system.

After completion of the reaction, the temperature was kept for 1 hour to evaporate and remove unreacted epichlorohydrin, and the reaction product was dissolved in methyl isobutyl ketone.

Next, after removing the by-product salt, methyl isobutyl ketone was evaporated and removed to obtain a solid resin at room temperature.

The softening point of this resin was 68 ° C. and the epoxy equivalent was 208.

The ¹³ C-NMR chart of this resin is shown in FIG.

The assignment of peaks in the ¹³ C-NMR chart in FIG. 2 is as follows.

29-32ppm 41-43ppm 44.8ppm 50.2ppm 68.8ppm Aromatic ring carbon 112-157ppm Example 2 Polymerization conditions were heated to 200 ° C in the same manner as in Example 1 (1), and further kept at 200 ° C for 2 hours. .

The softening point of the obtained resin was 133 ° C.

Further, this resin was glycidyl etherified in the same manner as in Example 1 (2) to obtain a solid resin at room temperature.

This resin had a softening point of 82 ° C. and an epoxy equivalent of 211.

Example 3 P-isopropylphenol filled with MnO ₂ type catalyst 60
The mixture obtained by dehydrogenation by passing through a reaction layer at 0 ° C. (p
-Isopropenylphenol 27 wt%, p-isopropenylphenol 65 wt%, p-isopropylphenol oligomer 6 wt%, cresols 1.5 wt%, unknown composition 0.5 wt
%) 300 g to obtain a yellowish brown resin in the same manner as in Example 1 (1).

The softening point of this resin was 99 ° C.

Further, this resin was polymerized in the same manner as in (2) of Example 1 to obtain a solid resin at room temperature.

The softening point of this resin was 62 ° C. and the epoxy equivalent was 208.

Example 4 1.0 mol of glycidyl ether of novolac type phenolic resin obtained in Example 1 (2) (as an epoxy group,
Specifically, 208 g), 1.0 mol of phenol novolac (as phenolic hydroxyl group), and 0.8 parts by weight of tris (dimethylaminomethyl) phenol (Sumicure D, manufactured by Sumitomo Chemical Co., Ltd.) as a curing accelerator are roll-kneaded. It was made into the composition.

Next, this composition was molded into a 1 mm sheet by pressing and heating.

This molded product was post-cured at 170 ° C. for 5 hours to prepare a cured molded product.

The glass transition temperature of this molded product was 236 ° C.

The elastic modulus at 25 ° C was 2.18 × 10 ⁹ N / m.

Example 5 A cured molded article was obtained in the same manner as in Example 4, except that the glycidyl ether of the novolac type phenolic resin obtained in Example 2 was used.

The glass transition temperature of this molded product is 254 ° C, and the elastic modulus at 25 ° C is
It was 2.22 × 10 ⁹ N / m.

Comparative Example 1 Currently, commercially available cresol novolac glycidyl ether (Sumiepoxy ESCN-22 manufactured by Sumitomo Chemical Co., Ltd.) is mainly used as an epoxy resin for semiconductor encapsulation.
A cured molded product was prepared in the same manner as in Example 4, except that the main component was 0, the softening point was 67 ° C., and the epoxy equivalent was 207).

The glass transition temperature of this molded article was 198 ° C., and the elastic modulus at 25 ° C. was 2.72 × 10 ⁹ N / m.

Comparative Example 2 Similar to Comparative Example 1, commercially available cresol novolac glycidyl ether (Sumiepoxy manufactured by Sumitomo Chemical Co., Ltd.)
Using ESCN-220, a softening point of 80 ° C., and an epoxy equivalent of 206) as a main component, a cured molded product was prepared in the same manner as in Example 1.

The glass transition temperature of this molded article was 219 ° C., and the elastic modulus at 25 ° C. was 2.81 × 10 ⁹ N / m.

<Effects of the Invention> The glycidyl ether of the novolac type phenolic resin of the present invention is higher than the glycidyl ether of cresol novolac that is generally marketed as a heat-resistant epoxy resin, and has a high glass transition temperature when it is a cured molded article, Moreover, the elastic modulus is low.

Originally, when the glass transition temperature is increased, the elastic modulus is also increased, but the epoxy resin from the glycidyl ether of the present invention is well balanced in this respect.

The encapsulant for electronic parts is required to have a low elastic modulus and heat resistance in order to reduce internal stress due to encapsulation. However, the encapsulant from the glycidyl ether of the present invention satisfies these requirements. Is very suitable for.

[Brief description of drawings]

FIG. 1 is a ¹³ C NMR chart of the novolac type phenolic resin obtained in Example 1 (1). FIG. 2 is a ¹³ C NMR chart of the glycidyl ether of the novolak type phenolic resin obtained in (2) of Example 1.

Claims (4)

[Claims] 1. Formula (III) (Wherein R ¹ , R ² and R ³ are each selected from the group consisting of hydrogen atom, hydrocarbon group and halogen atom, and n is a number from 2 to 50) Glycidyl ether. 2. Formula (IV) (Wherein R ¹ , R ² and R ³ are each selected from the group consisting of a hydrogen atom, a hydrocarbon group and a halogen atom, and n is a number of 2 to 50). Glycidyl ether of the novolak type phenolic resin according to the item (1). 3. Formula (III) (Wherein R ¹ , R ² and R ³ are each selected from the group consisting of hydrogen atom, hydrocarbon group and halogen atom, and n is a number from 2 to 50) An encapsulating material containing glycidyl ether as a main component. 4. Formula (IV) (In the formula, R ¹ , R ² and R ³ each represent a hydrogen atom, a hydrocarbon group, and a halogen atom,
The sealing material according to claim (3), wherein n represents a number of 2 to 50).